Motor controller system for battery-powered motors

• US 6,750,622 B2
• Filed: 09/26/2002
• Issued: 06/15/2004
• Est. Priority Date: 05/05/2000
• Status: Active Grant

• Current Assignee: Advanced Materials Corporation
• Original Assignee: Advanced Materials Corporation
• Inventors: Simizu, Satoru, Sankar, Suryanarayan G., Obermeyer, Richard T., Cho, Y. Sean, Margolin, Arkady
• Primary Examiner(s): Nappi, Robert
• Assistant Examiner(s): Smith, Tyrone
• Application Number:
  US10/240,078
• Publication Number:
  US 20030222607A1
• Time in Patent Office: 628 Days
• Field of Search: 318/139, 318/430, 318/432, 318/434, 318/440, 318/254, 388/800, 388/801, 388/809, 388/901.5, 388/937
• US Class Current: 318/139
• CPC Class Codes: A01D 34/006 Control or measuring arrangements
• CPC Class Codes: A01D 34/78 electric
• CPC Class Codes: B60L 50/52 characterised by DC-motors
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10S 388/937 Hand tool

Abstract

A motor controller system (15a) for dc power source motors (10) which includes a sensor device (16) that operates to measure and generate a voltage signal from the motor current and the rate of change of said current, and a programmable input/output processor (12) which receives voltage signals as input from the motor current, dc power source (11) and/or motor (10) and compares on or more of these voltage signals to one or more control parameters. Based upon these comparisons, the processor (12) generates a pulse width modulation control signal, which triggers a switching mechanism (14) and related interrupt service routing to make adjustments to the operational parameters of the motor by periodic interruption of the motor current.

Claims

1. A motor controller system for dc-powered motors comprised of a dc power source, a motor and corresponding circuit, said motor control system being effective to maximize motor efficiency and extend the life of said dc power source, and comprising:

a. a current sensor device which measures the current of said motor and the rate of change of said current and generates a corresponding voltage signal;

b. a programmable input/output processor which receives as input said current sensor voltage signal and a voltage signal from the dc power source for said motor, compares one or more of said voltage signals to at least one corresponding control parameter, and, based upon said comparison, generates a control signal which is comprised of the duty cycle of a pulse width modulation signal; and

c. a switching mechanism which receives said control signal and, based on said control signal, periodically interrupts said motor current and thereby makes adjustments to the operational parameters of said motor, said control signal further triggering an interrupt service routine which synchronizes the routine of said current sensor device and processor so that said routines occur after a fixed delay from completion of the routine of said switching mechanism.

2. The motor controller system of claim 1, wherein said sensor device for said motor current is placed in series with said motor, such that said motor is positioned between said switching mechanism and said motor current sensor device, and said motor and said motor current sensor device are in parallel to an additional circuit path with a protection diode, said protection diode acting to dissipate current and voltage resulting from the inductance of said motor when said switching mechanism is open and thereby protect said switching mechanism from destructive high voltage.

4. The motor controller system of claim 1 or 3, wherein said switching mechanism is a semiconductor switch selected from the group consisting of a bipolar transistor, a metal oxide semiconductor field effect transistor (MOSFET) and an insulated gate bipolar transistor (IGBT).

5. The motor controller system of claim 1 or 3, wherein said processor also receives as input and analysis a voltage signal from said motor in generating said control signal.

6. The motor controller system of claim 1 or 3, wherein said voltage signals are conditioned before being input to said processor to filter out any rapid changes in said voltage signal and any circuit noise caused by the operation of said motor.

7. The motor controller system of claim 1 or 3, wherein, in response to operator input, said control parameters can be adjusted.

8. The motor controller system of claim 1 or 3, wherein, in response to operator input, said processor can be adjusted to analyze voltage signals and generate corresponding control signals which adjust the operational parameters of said motor in respect to either dc power source voltage, motor speed or motor torque.

9. The motor controller system of claim 1 or 3, wherein said adjustments to the operational parameters of said motor are made to obtain substantially constant voltage output, and said processor:

a receives said dc power source voltage signal as input;

b. utilizes a control parameter corresponding to a desired dc power source voltage level;

c. compares said dc power source voltage signal with said control voltage by periodically calculating the ratio of said dc power source voltage to said control signal voltage; and

d. generates a control signal based on said ratio.

10. The motor controller system of claim 1 or 3, wherein said adjustments to the operational parameters of said motor are made to obtain substantially constant speed, and said processor:

a. receives and utilizes said measurement of said dc power source voltage signal and said motor current and motor current rate of change voltage signals as inputs and determines the speed of said motor based on said inputs;

b. utilizes a control parameter corresponding to desired motor speed;

c. compares said measured motor speed with said control speed; and

d. generates a control signal based on said comparison of said measured motor speed with said control motor speed.

11. The motor controller system of claim 1 or 3, wherein said adjustments to the operational parameters of said motor are made to obtain substantially constant torque, and said processor:

a. receives and utilizes said motor current voltage signal as input and determines the torque of said motor and the rate of change of said torque based on said input;

b. utilizes a control parameter corresponding to desired torque;

c. compares said measured torque with said control torque; and

d. generates a control signal based on said comparison of said measured torque with said control torque and the rate of change of said measure torque.

12. The motor controller system of claim 11, wherein said control signal is determined to achieve a smooth and rapid convergence to said desired torque operating parameter by multiplying a constant to the difference between said desired torque and said measured torque.

13. The motor controller system of claim 1 or 3, wherein said control signal is determined to achieve a smooth and rapid convergence to said desired torque operating parameter by multiplying a constant to the difference between said desired torque and said measured torque;

and said determination of said control signal further includes use of a scaling factor which, through the control signal, increases torque if said measured torque is less than said desired torque and decreases torque if said measured torque is greater than said desire torque.

14. The motor controller system of claim 1 or 3, wherein said control signal is determined to achieve a smooth and rapid convergence to said desired torque operating parameter by multiplying a constant to the difference between said desired torque and said measured torque;

and said determination of said control signal further includes use of a factor proportional to the rate of change in said measured torque which, through the control signal, adjusts said measured torque downward if said rate of change is too high.

15. The motor controller system of claim 1 or 3, wherein said current sensor device is comprised of a resistor connected in series with the motor winding of said motor and a differential amplifier.

16. The motor controller system of claim 1 or 3, wherein said current sensor device is a Hall sensor chip.

3. A motor controller system for dc-powered motors comprised of a dc power source, a motor and corresponding circuit, said motor control system being effective to maximize motor efficiency and extend the life of said dc power source, and comprising:

a. a current sensor device which measures the current of said motor and the rate of change of said current and generates a corresponding voltage signal;

b. a programmable input/output processor which receives as input said current sensor voltage signal and a voltage signal from the dc power source voltage for said motor, compares one or more of said voltage signals to at least one corresponding control parameter, and, based upon said comparison, generates a control signal in the form of the duty cycle of a pulse width modulation signal;

c. a switching mechanism which receives said control signal and, based on said control signal, periodically interrupts said motor current and thereby makes adjustments to the operational parameters of said motor, said control signal further triggering an interrupt service routine which synchronizes the routine of said current sensor device and processor so that said routines occur after a fixed delay from completion of the routine of said switching mechanism; and

d. a protection diode positioned in an additional circuit path parallel to both said sensor device for said motor current and said motor, said motor and said motor current sensor device being placed in series with said motor positioned between said switching mechanism and said motor current sensor device, said protection diode acting to dissipate current and voltage resulting from the inductance of said motor when said switching mechanism is open and thereby protect said switching mechanism from destructive high voltage.